1. Field of the Invention
The present invention relates to a method for producing a semiconductor optical device and a semiconductor optical device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2008-205025 discloses an optical semiconductor device and a method for producing the optical semiconductor device. In this method, a p-type contact layer and an upper cladding layer are processed into a ridge shape by dry etching or the like to form a ridge portion. A silicon oxide film having a thickness of 400 nm is then formed on the entire surface by chemical vapor deposition (CVD). Subsequently, a bisbenzocyclobutene (BCB) resin is applied to the entire surface and cured. Thus, a resin layer having a thickness of 2 μm is formed. The resin layer has a substantially flat surface. Next, a photoresist film is formed on the resin layer. The photoresist film covers a region other than a region that is located along the ridge portion and whose width is larger than that of the ridge portion. The resin layer and the silicon oxide film are successively etched using the photoresist film as a mask. Thus, the upper surface of the p-type contact layer located on the ridge portion is exposed. The photoresist film is then removed. Subsequently, a silicon nitride film having a thickness of 300 nm is formed on the entire surface by plasma CVD. A photoresist film is formed on the silicon nitride film, the photoresist film serving as a mask having a pattern that covers a region other than a region where a p-type electrode is to be formed. By etching the silicon nitride film using the mask, a contact window is formed above the ridge portion and the upper surface of the p-type contact layer is exposed. The photoresist film is then removed, and a p-type electrode is formed on the silicon nitride film and in the contact window. Except for the contact window region above the ridge portion, the surface of the substrate and the side surfaces of the ridge portion are embedded with the BCB resin.